Medical amplifiers can be implemented for a variety of devices used in connection with patient treatment procedures and/or medical diagnoses. Medical amplifiers can be configured in a manner to isolate a patient from any possible contact with a power source, such as including line voltage and earth ground. Isolation can be implemented in a variety of ways, such as magnetic or optical isolation, to pass signals between a control system and portions of the device that might contact the patient. Some types of isolation can result in the medical amplifier being more susceptible to radiated noise, such as line frequency noise, based on the patient ground not being coupled with earth ground. In these situations, a substantially large common-mode voltage with respect to earth ground can be generated, such that the common-mode voltage generates a current flow from the patient to earth ground via a parasitic capacitance, thus generating a differential voltage that cannot be rejected by the medical amplifier.